Handling and
treatment of male European eels (Anguilla
anguilla) for hormonal maturation and sperm cryopreservation
J.G.
Herranz-Jusdado, E. Kása, T. Kollár, V. Gallego, D.S. Peñaranda, C. Rozenfeld,
L. Pérez, Á. Horváth, J.F. Asturiano
During the last
years, several research groups have been working on the development and
improvement of new protocols for the European eel handling and maturation. As
of yet, weekly injections of human chorionic gonadotropin (hCG) have proved to
maturate males after just 5-6 weeks of treatment, producing high volumes of high-quality sperm during several weeks. In
addition, sperm cryopreservation protocols using different extenders, cryoprotectants
and cooling and thawing times have been previously described for European eel.
Here, we show that Tanaka´s extender solution can be directly used for
fertilization or for cryopreservation, making unnecessary the usage of
different types of solutions and dilutions. Furthermore, the use of methanol as
a cryoprotectant makes this protocol easy to use as methanol has low toxicity
and does not activate the sperm. The
sperm does not need to be cryopreserved immediately after the addition of the
cryoprotectant, and it can be used long after being thawed. Moreover, sperm
motility is still high after thawing although it is lower than that of fresh
sperm. The aim of this work is to show the best available protocol for European
eel handling, maturation, and sperm
cryopreservation.
